diff options
| -rw-r--r-- | main.c | 15 |
1 files changed, 11 insertions, 4 deletions
@@ -128,12 +128,12 @@ process0(void) p0->cwd = iget(rootdev, 1); iunlock(p0->cwd); - // dummy user memory to make copyproc() happy. - // must be big enough to hold the init binary. - p0->sz = PAGE; + // Dummy user memory to make copyproc() happy. + // Must be big enough to hold the init binary and stack. + p0->sz = 2*PAGE; p0->mem = kalloc(p0->sz); - // fake a trap frame as if a user process had made a system + // Fake a trap frame as if a user process had made a system // call, so that copyproc will have a place for the new // process to return to. p0->tf = &tf; @@ -142,6 +142,13 @@ process0(void) p0->tf->cs = (SEG_UCODE << 3) | DPL_USER; p0->tf->eflags = FL_IF; p0->tf->esp = p0->sz; + + // Push bogus return address, both to cause problems + // if main returns and also because gcc can generate + // function prologs that expect to be able to read the + // return address off the stack without causing a fault. + p0->tf->esp -= 4; + *(uint*)(p0->mem + p0->tf->esp) = 0xefefefef; p1 = copyproc(p0); |